Ranging from 1-5 cm in length, these small social groomers like to hang out in large groups (up to 100) under the coral reef ledges and overhangs of the Indo-Pacific.

Part of the decapod crustacean subphylum-- they are the Rhynchocinetes durbanensis, also known as the Hingebeak Durbanensis Shrimp.

Image credit: Fiona Ayerst

The derived family name of these shrimps (Rhynchocinetidae) means ‘movable beaks’--- indicating their beak like rostrum that can bend. This rostrum can also be used for attack or defense from predators if need be.

Image credit: Fiona Ayerst

Although their diet mainly consists of small crustaceans, fine algae and carrion – the Hingebeak Durbanensis are specifically known for their diligent cleaning habits and symbiotic relationships with various fish.

The Hingebeaks (along with other types of shrimp) have antennae, which have sensors on them that allow the animals to “smell”, “taste” and feel where they touch. Typically, long antennae help the shrimps orientate themselves regarding immediate surroundings-- while shorter antennae help judge what is and is not prey.

Lionfish

Mantis Shrimp (Image credit: Levi, Guinjata Dive Centre)

Solefish

Scorpionfish

There are some fish the Durbanensis do steer clear from-- such as lion fish, solefish, mantis shrimp, and scorpionfish (due to being the shrimps natural predators.)

Image credit: Kim Vu

The Hingebeaks “job” in the ocean is to reside at natural 'cleaning stations', to help keep rid of dead skin and parasites off of their “friends” while gaining nutritional value from the parasites. There was a rumor that sometimes they even take on humans as their clients... So on the next dive, I decided to see for myself.

After arriving at a dive site called Levi’s Ledge (with courtesy of Guinjata Bay Diving Centre) I was shown one of these 'cleaning stations' where the shrimps typically reside.

I completely emptied out all of the air in my BCD and laid on the ocean floor, right next to the overhang where the shrimps were. I noticed that the more movement I made, the more wary the shrimps were of my presence. I began to slow my breath much more than before (never holding my breath, of course - Scuba Diving 101) and lay as still as possible (given the surge and ocean currents).

Image credit: Fiona Ayerst

The first shrimp to climb on my hand had initially felt my fingers with her antennae for a few minutes to make sure I was a safe customer. Once one decided to climb on and begin cleaning my cuticles, the others slowly made their way on my hand as well. It was amazing to interact with these little ‘ocean maids’, and to feel their miniature claws, as they worked so hard at tearing away any dead skin.

Image credit: Fiona Ayerst

Image credit: Fiona Ayerst

With some patience, a few of us even dared to get our mouths “cleaned” as well.

Image credit: Cullen Welch, Matt Dobson

The video below created by Martin Totland, shows a Yellow-mouth Moray Eel's relationship with these shrimps at the 2:30 mark and again with one of our groups members interaction at the 2:50 mark.

Male Hingebeaks have much larger claws than the females, and most of the shrimp which cleaned our hands were in fact female. I realized this only when I spotted one with claws larger than his eyes.

Male Hingebeak to the right (Image credit: Fiona Ayerst)

The Hingebeaks eyes are some of the coolest I have ever encountered. Their eyes are located on the tips of two stalks coming from the head, with pupils appearing as if they are made of geometric shapes.

Image credit: Kim Vu

Most prawns, as well as the Hingebeaks, have panoramic vision and compound eyes-- which are very good at detecting any movement. The term 'compound eye' means that the eye itself contains thousands of individual receptors and a single image is broken up into a combination of inputs. Each input is located on a convex surface and points in a slightly different direction. Compared to our eyes, a shrimp’s eye can detect fast movement and possesses a very large angle of view.

Image credit: Kim Vu

Hope you enjoyed this post on these teeny ocean maids! Now go do some diving.